Pavement.



G. P. WALTER.

PAVEMENT.

APPLICATION TILED OOT.29, 1906.

Patented Sept. 23, 1913.

fNVL NTO/e.

A froze/v15 1 5 WITNESSES CHARLES P. WALTER, OF HARRISBURG, PENNSYLVANIA.

PAVEMENT.

Specification of Letters Patent.

Application filed October 29, 1906.

i *atented Sept. 23, 1913.

Serial No. 341,196.

lb all u /1. own it may concern Be it known that I, Cnannus P. ar/ran. a citizen of the United States, residing at Harrisburg, in the county of Dauphin and State of .lennsyh'ania, have invented a new and useful Pavement, of which the following .is a specification.

This invention relates to pavements and more particularly to a process of laying the same.

It is well known thatin preparing foundations or road beds from previously mixed concrete, that the cement will occupy much of the space between the pieces of broken stone, and if this cement is disturbed while setting by rolling, tamping, or similar operations, it will soon disintegrate, this being especially the case where from careless han dl'ing the concrete mixture allowed to remain for a long period of time before being placed in position in the formation of the foundation or road bed. A further disadvantage found in ordinary concrete road beds that where the surfaces are rolled smooth, it is unsuitable for horses, and accidents through slipping or falling of the animals are frequent occurrences.

In the accompanying drawings :--Figurc 1 is a sectional elevation of a road bed illustrating the first step in construction. Fig. 2 is a similar view after the grouting has been applied and the surface rolled. Fig. 3 is a similar view of a portion of a. finished road bed showing the application of the finishing layer of small broken stone or gravel.

In carrying out the invention, the street is excavated to the proper depth as at l, and a layer of broken stone 2 is placed thereon, the layer of stone being made as even and regular as 'iossible, but without any rolling or tamping. Into this layer of broken stone is poured a grouting 3 formed of a mixture of cement, very fine sand and Water, the mixture being preferably thinned down to about the consistency of cream, so that it may flow freely between the broken stone and fill up the interstices from top to bottom. This grouting mixture is freshly prepared and applied as soon as made, so that there is no opportunity for it to set before the rolling operation. The grouted stone is then rolled, and under this pressure it is found by experience that as the layer of stone is pressed firmly together, the milklike grouting will be forced upward and will rise to the top of the layer of stone, so as to form at the top a relatively thick layer i of mixed cement and sand the. density of which. gradually decreases toward the bottom of the layer of stone, and when the cement hardcns this comparatively thicklayer at the top will exclude moisture and form a water proof road bed.

Inasmuch as the smooth layer of cement would afford insecure footing for horses, and permit wagons, automobiles, etc., to slide, a layer 5 of finely crushed stone or gravel or any adaptable grit or sand is placed over this layer of cement before the latter has set, and this finer layer will be come embedded in the smooth cement to a greater or less extent and afford a slightly rough, gritty surface, and will afford a good footlmld, and in the course of time, this upper layer will be ground down in much the same manner as a macadam road.

I claim The hereindescribed process of constructing a road or pavement, said process consisting in forming an excavation, placing a layer of uncoated stone in said excavation and arranging said stone so as to form a substantially smooth upper surface, pointing a thin cement grouting over the stone prior to rolling the same, rolling the stone to force the grouting to the upper surface there of so as to form a plastic tread surface, and finally, while the tread surface is still in a plastic state, placing thereon without the applieatirm of pressure a covering of finely crushed stone or gravel whereby the surface of the pavement is left in a slightly roughened and gritty condition, said crushed stone or gravel completely covering the plastic material.

In testimony that T. claim the foregoing as my own, I have. hereto aflixed my signature in the presence of two witnesses.

(II In RLES P. \VAIJTIER.

\Vitnesses:

C. E. Corns, ROLAND G. Boo'rn.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. G. 

